The Syndicate War, a conflict lasting several months, erupted during the Galactic Empire's imperial era following the Attack on the Executor. This attack and the subsequent war were orchestrated by the revitalized criminal organization Crimson Dawn as part of a secret war led by Lady Qi'ra. Her aim was to dismantle the reign of the Sith Lords Darth Sidious and Darth Vader over the galaxy, thereby establishing a new power dynamic. The war triggered infighting among various syndicates and groups, destabilizing the criminal network. Upon uncovering the plot against him, Sidious intervened to crush Crimson Dawn, contacting the leaders of the warring syndicates and commanding them to cease their futile conflict, instead focusing on locating and eliminating Qi'ra.
Qi'ra and her associates initiated the war by spreading misinformation among other syndicates. They falsely claimed that, following the Empire's destruction of the Hutt Council due to their involvement in the Attack on the Executor, the Empire sought a new partner to replace their exclusive agreement with the Hutts. Simultaneously, Qi'ra discreetly employed the bounty hunter Chanath Cha and the Orphans to attack the syndicates. Uncertain of who was responsible, the syndicates blamed one another. This distrust, coupled with the rumor of the Empire seeking the strongest syndicate, instigated open warfare between them. As Qi'ra anticipated, Darth Sidious, publicly known as Emperor Sheev Palpatine, took notice of the conflict and directed Darth Vader to intervene.
Following the war's commencement, Sidious instructed Grand Vizier Mas Amedda to order General Maximilian Veers and Admiral Firmus Piett to deploy the Imperial fleet to suppress it. The war persisted for several months. Eventually, Sidious deduced that the Syndicate War, along with other recent events, indicated a specific enemy exploiting the chaos to conceal their true objectives. Summoning Vader to the Imperial Palace, Sidious and Vader met with Director Barsha from the Imperial Security Bureau's division responsible for monitoring the criminal underworld, who had analyzed the ongoing conflict. Barsha revealed that Crimson Dawn had engineered the war by spreading the initial rumor. In response, the Sith commanded the entire Imperial Military to locate Crimson Dawn's flagship, the Vermillion, prompting Qi'ra to activate her agents within major galactic factions, including the Empire, to initiate widespread chaos as the beginning of her "Hidden Empire."
Palpatine personally ended the Syndicate War by contacting the heads of the warring crime families. He reminded them of his galactic authority and demanded they cease what he described as a "pointless" conflict. Exposing Crimson Dawn's manipulation of galactic events, Palpatine ordered them to redirect their resources and efforts towards eliminating Crimson Dawn, promising to reward any syndicate that killed Qi'ra and delivered her remains. Although the war disrupted the criminal underworld, some syndicates, such as the Pykes, quickly resumed their operations. After Crimson Dawn's downfall and the failure of Qi'ra's plans, the war and its associated events were documented in a holocron by the Archivist, a Force-sensitive individual who had allied with Qi'ra in her scheme. The Syndicate War was also referenced in "Index of Organizations," a survival guide distributed by Carson Teva during the New Republic Era.